This invention relates to the art of spreading materials such as salt, cinders or gravel, on roadways and, more particularly, to an improved hopper for use on a vehicle employed in spreading material on a roadway. While the invention is particularly applicable for use on a vehicle for spreading salt on a roadway during the winter season and will be described with particular reference thereto, it is appreciated that the invention has broader applications and can be used for vehicles spreading various materials along the roadway or path being traveled by the vehicle.
During the winter season, it has become common practice to spread salt or cinders along a roadway to remove ice and reduce the tendency for skidding of motor vehicles traveling along the roadway. While many arrangements for spreading salt or cinders have been attempted, the most accepted devices include a broadcast spreader having a rotating disc which centrifugally discharges salt or cinders dropped on the spreader from a dump bed carried by the vehicle as the vehicle moves along the roadway. Since the broadcast spreader generally has a width substantially less than the width of the dump bed of the vehicle, provisions must be made for channelling the salt or cinders falling from the dump bed to an area immediately above the broadcast spreader. A hopper device extending along a discharge end of the dump bed is customarily used to channel the particulate material onto the spreader. These hoppers generally include spaced end walls, a backwall positioned adjacent to and directly beneath the discharge end of the dump bed, and a front wall deflecting the particulate material into the hopper. A rotating auger is provided near the bottom of the hopper for the purpose of moving the particulate material to a discharge opening in the bottom of the hopper from which the salt or cinders drop onto the broadcast spreader. While the discharge opening may be located at any position along the hopper, generally the opening is located at the end of the hopper nearest the center of the roadway being traveled. As a result of the location of the discharge opening, the rotating auger is required to move portions of the particulate material the entire length of the hopper toward the end wall nearest the roadway center. This combination of hopper, rotating auger and broadcast spreader is widely used in spreading salt or cinders along roadways.
While the hopper and broadcast spreader combination is beneficial during use as a spreader, even an occasional necessity of dumping particulate material directly onto the roadway presents problems. In this regard, if a larger quantity of material or a wide path of material were desired to be deposited on the roadway, the hopper device would have to be removed from the vehicle. To overcome this difficulty, it has been proposed that the hopper include a movable cover plate having a first position for spreading and a second position for dumping. A device having such a movable cover plate is shown in Swenson, U.S. Pat. No. 3,189,355. This reference teaches of a cover plate movable into a vertical position for spreading in which position the cover plate provides a backing plate for directing particulate material into a hopper. Moving the cover plate to a horizontal position allows dumping of particulate material over the hopper. This concept of providing a cover having spreading and dumping positions is a commonly utilized design as shown by Daneman, U.S. Pat. No. 3,349,970 and Buchmann U.S. Pat. No. 3,438,585.
Another problem which commonly occurs in salt or cinder spreaders having hopper devices and rotating augers is clogging of the salt or cinders within the hopper surrounding the auger. In the spreader devices discussed above, the hopper has an inlet through which the particulate material enters from the dump bed and a relatively small discharge opening through which the material falls onto the spreader. Salt or cinders being spread often clog the auger, especially if it becomes damp or is allowed to sit for a prolonged time in the hopper. The design of the hopper as an enclosed device results in considerable effort being expended to unclog the hopper and auger. As a solution to this problem it has been proposed that the hopper be provided with an arrangement allowing access to the auger for cleaning. Such an arrangement is shown in a Swenson, U.S. Pat. No. 3,510,066. A lower portion of a hopper is pivotally mounted at a bottom edge to enable the portion to be dropped for cleaning of the hopper and access to the auger. The pivoting lower portion extends the entire longitudinal length of the hopper. This reference requires a first movable panel for dumping and spreading and a second movable panel for clean-out of the hopper.
An improvement upon this immediately above noted concept is shown in Hetrick, U.S. Pat. No. 4,157,150 wherein spreading, dumping and cleaning are provided by a single positionable panel of a hopper device. The panel is permanently secured to the hopper by links pivotally mounted on a pair of spaced sidewalls and the sides of the panel resulting in the panel being movable relative to the hopper through spreading, dumping and cleaning positions. Locking pins are appropriately positioned through a series of apertures in each of the sidewalls. Corresponding apertures in the panel provide releasable locking of the panel by the pins in the spreading and dumping positions.